
The Good Sister follows a couple who is working to put their crumbling marriage back together, when the wife receives a letter informing her that she has a long-lost twin sister. First thinking that the new family member will bring the couple closer together, the husband then begins an affair with the sister and discovers that she is treacherous and dangerous.

Sonya Walger
Kate / Linda

Ben Bass
Jack McLennan

Bobbie Phillips
Mrs. Nelles

Ashleigh Harrington
Cassie

Alarey Alsip
Deb

Michael Hearn
Walberg

Noel Burton
Langler
Sam Stone
Cab Driver
Emma Dimig
Twin Girl #1
Sonia D'amico
Twin Girl #2
Howard Harris
Older Man

Simon Anthony
Police Officer

Yanik Ethier
Guy

Lyriq Bent
Investigator

Kathleen Glynn de Santiago
Mother (as Kathleen Glynn)